Charles Gilbert Thiel

CHARLES GILBERT THIEL, 94, of Tucson, AZ, formerly Maplewood, MN, passed away on March
10, 2023. Charles, the son of Doris Duncan and Clarence Thiel, grew up in Summerland, CA just
outside of Santa Barbara.
During high school Charlie worked at Weston's Camera Shop in Santa Barbara, and
subsequently served in the U.S. Army Air Corps as a photographer while stationed in Japan.
After his military deployment, he desired a career in photography, but given the lack of
photography jobs at the time, he decided to pursue the field of chemistry. He attended the
University of California Santa Barbara, and graduated in 1954 with a BA in Chemistry. Upon
graduation, he joined Riker Laboratories. There he led a storied 46-year career that
revolutionized inhalation drug delivery, rising to Division Scientist in what later became the
Drug Delivery Systems Division of 3M Pharmaceuticals.
Charlie was joint inventor of the first pressurized metered dose inhaler (pMDI) that was
developed by a small team at Riker Laboratories in 1956 to treat asthma. He changed the
inhaler formulation design from one using 50 percent alcohol (which burned patients' nostrils
when administered as a nasal spray) to one using an innovative suspension of the medication in
a liquefied gas propellant -- a design still used worldwide today. His passion for high-speed
photography remarkably gave insight into the behavior of aerosol sprays imperative to the
invention.
The invention of the MDI revolutionized the field of respiratory drug delivery and Charlie is a
legend in this field. His critical contributions to the development of MDIs dramatically improved
the quality of life for hundreds of millions of people and have saved countless lives. Charlie's
dedication to the field was made evident by his continued contributions to the United States
Pharmaceopeia (USP) long past his retirement.
Charlie will be remembered for his pioneering and innovative spirit, as well as his passion for
storytelling, photography, and science, especially the ability of science to improve the lives of
others. He had a wonderful sense of humor, a curiosity about everything, and loved his family,
the ocean, travel, classical music and opera. Charlie is predeceased by his parents, sisters
Marilynn and Joy, and great granddaughter Isis. He will be lovingly remembered by his wife of
36 years, Carol, daughter Emma, sons Chuck and Walter, stepdaughters Anne and Sara,

stepsons Eric and Jason; as well as 11 grandchildren and 2 great grandchildren. At his request,
his ashes will be scattered in the Channel Islands off the coast of Santa Barbara.